6-24-03 SE SD Tornado Outbreak
A cyclic supercell produces 15 tornadoes between Vermillion, SD and Davis, SD
A true wonder of nature
Chase log and photos by Melanie Metz and Peggy Willenberg
24 June 2003 found StormTours.com on tour in Nebraska once again. Our target for the day was the area between O'Neill, Nebraska and Sioux Falls,South Dakota, somewhere on the stationary boundary. As we were driving south, we noted an area of "billow clouds" just north of the boundary-this area of enhanced horizontal vorticity would prove to be significant later in the day.
Driving west on highway 20 towards O'Neill, we had 90/73 and a very nice Cu field overhead. We made a point to keep an eye to the east as we slowly worked west--soon we spotted a nice looking tower going up in the Norfolk area. So it was back to the east and trying to decide how to deal with river crossings to get back into South Dakota. We targeted a SVR and later TOR warned cell in SE South Dakota, and shortly after crossing the river at Yankton, headed east towards Vermillion. It was interesting to note that this cell became SVR just north of the boundary in the area of increased horizontal vorticity.
We intercepted the cell just north of Vermillion--at this point it had a nice rotating wall cloud and had just dropped golf ball size + hail. We followed it east as it produced several nice wall clouds, but no tornado. Clearly the cell was pulsing and regenerating itself, and finally produced an incredibly upright and robust tower with a huge wall cloud below. As we watched, strong warm inflow poured into the updraft area and it put down several needle funnels simultaneously. The show had begun.
For the next two hours the supercell moved slowly north and produced just about every type of tornado that could be imagined. At one point, three separate tornadoes were on the ground emerging from different parts of the meso. As the storm neared Centerville, S.D., it appeared to intensify. A farmhouse was severely damaged, the shelter-belt trees were stripped and the barn demolished. Fortunately the occupants were in their basement at the time and survived without injury. Also in this area, the remains of a roof partially blocked the road and made it difficult to continue pursuit. We managed to get through and followed the storm until after dark in the area of Davis, S.D. Based on our tally, we saw 15 tornadoes from this storm.
Our guests were overwhelmed with the immensity of the event, as were we. But the day wasn't finished with us. We stopped for dinner in Sioux Falls, and noticed the increasing pitch and intensity of the wind as we ordered our meals.
Shortly thereafter, the restaurant manager gave us the news that a tornado had touched down five miles to the west, and herded us all into the walk-in refrigerator! After a few moments we emerged to see heavy rain and high winds, but fortunately no tornado nearby.
It was a day we will always remember.
Peggy Willenberg--Melanie
Metz
Twistersisters.com